This invention relates to improvements in interfolding machines in which webs of paper are interfolded into bundles which can be severed into appropriate lengths for facial tissues or other sanitary products.
Facial tissues are conventionally packaged in an interfolded relation, so that as one tissue is removed from its container, the succeeding tissue will be raised to an accessible position, and so on. Machines for interfolding webs of tissue are well known, as evidenced by Marcalus et al U.S. Pat. No. 3,850,425, dated Nov. 26, 1974, and Marcalus et al U.S. Pat. No. 4,061,325 dated Dec. 6, 1977. The first named Marcalus et al patent is particularly unique for its disclosure of a highly simplified and compact mechanism for interfolding webs of tissues, and this disclosure is incorporated by reference as if set forth at length herein. The present invention is an improvement thereon over the above-mentioned inventions.
In accordance with principles disclosed in the first named Marcalus et al patent, roll-wound webs of tissue paper are arranged in a semi-circular array, with the webs converging to a central conveying mechanism. Folding assemblies are deployed to interfold adjacent webs as the webs are pulled by the conveyor structure. Consequently, there is formed by the machine a bundle of interfolded webs of tissue paper. This web bundle is subsequently cut into stacks of appropriate lengths and a plurality of such stacks can be packaged in a typical slotted tissue container. As each tissue is withdrawn from the container, the succeeding tissue, due to ints interfolded connection with the previous tissue, is lifted to an accessible position for subsequent withdrawal.
It is desirable that the tissues be packaged in quantities of about one hundred or more per container. In order to accomplish this in an efficient manner, it is desirable to employ a plurality of interfolding machines so that a series of bundles are individually formed and deposited one upon the other to provide a bundle group containing the required number of tissues to fill a container. It will be appreciated that by merely depositing one bundle onto another, the lower web of the top bundle will not be interfolded with the upper web of the bottom bundle. At this point during tissue withdrawal there would occur a disruption in the automatic lifting of tissues to a withdrawal position. This problem is alleviated by the invention disclosed and claimed in the aforementioned Marcalus et al U.S. Pat. No. 4,061,325 in which merging stations are provided for joining bundles together. At the merging station the lower web half of the top bundle, and the upper web half of the bottom bundle, are passed along parallel surfaces which are inclined relative to vertical. At a downstream location the bundles converge and these web halves are automatically interfolded together. Thus, an interfolded relationship of all webs in the bundle group is established. In practice, it is necessary for an operator to manually position the lower and upper web halves onto the inclined surfaces. An operator is usually charged with replacing empty rolls of tissue on the interfolding machine, and threading the tissue web through the web-folding components of the machine, and thus cannot always direct sufficient attention to conditions at the merging station. Therefore, it would be advantageous if proper positioning of the upper and lower web halves could be accomplished at the merging station with minimal reliance upon the operator.
It is, therefore, an object of the present invention to deal with problems of the type noted above.
It is another object of the invention to provide novel methods and apparatus for merging bundles of webs together so that the lower web half of the top bundle and upper web half of the bottom bundle are interfolded.
It is a further object of the invention to provide such novel methods and apparatus which require minimal operator attention.
It is yet another object of the invention to provide methods and apparatus for automatically causing the lower web half of a top bundle and the upper web half of a lower bundle to be positioned along parallel inclined surfaces at a bundle merging station.